Optical diagnosis of colorectal polyps using high-definition i-scan: An educational experience

Table 1 Classification system for diagnosis of non-adenomatous and adenomatous colorectal polyps using high-definition i-scan (ICE classification)

	Non-adenomatous	Adenomatous
Color	Pale	Reddish
	Similar to adjacent mucosa	Different from adjacent mucosa
	Indiscrete borders	Clearly demarcated
Surface pattern	Round pits of uniform size, no definite pits	Oval, tubular or branched pits
Vessel pattern	Isolated, lacy vessels	Dilated, irregular vessels

Table 2 Endoscopic and pathologic characteristics of the colorectal polyps incorporated in our test set n (%)

Characteristic	Polyps
Total number of colorectal polyps	50
Location1
Proximal colon	25 (51.0)
Distal colon	24 (49.0)
Size1
Diminutive	32 (65.3)
Non-diminutive	17 (34.7)
Morphology1
Polypoid	29 (59.2)
Non-polypoid	20 (40.8)
Histopathology
Tubular adenoma	29 (58.0)
Tubulovillous adenoma	6 (12.0)
Carcinoma	1 (2.0)
Hyperplastic polyp	8 (16.0)
Sessile serrated adenoma/polyp	1 (2.0)
Other (i.e., inflammatory)	2 (4.0)
Normal tissue	3 (6.0)
Final histopathology
Non-adenomatous	14 (28.0)
Adenomatous	36 (72.0)
Image quality
Excellent	29 (58.0)
Less than excellent	21 (42.0)

¹Information was missing in 1 case.

Table 3 Frequencies of endoscopic features predictive of adenomatous and non-adenomatous polyps

	Adenomatous polyps	Non-adenomatous polyps
Features predictive of adenomas
Reddish	62.6%	2.6%
Different adjacent mucosa	74.7%	11.7%
Clearly demarcated	72.5%	33.1%
Oval, tubular or branched pits	71.7%	11.0%
Thick vessels	40.9%	8.4%
Features predictive of non-adenomas
Pale	32.3%	92.9%
Similar adjacent mucosa	22.5%	85.7%
Indiscrete borders	26.0%	65.6%
Round pits of uniform size, no definite pits	18.9%	73.4%
Isolated, lacy vessels	42.9%	87.0%
Features unclear
Color	5.1%	4.5%
Adjacent mucosa	2.8%	2.6%
Demarcation	1.5%	1.3%
Surface pattern	9.3%	15.6%
Vessel pattern	16.2%	4.5%

Table 4 Diagnostic performances of the eleven endoscopists in predicting polyp histology subdivided according to level of experience, location, size, morphology and image quality

	Sensitivity	Specificity	Accuracy	PPV1	NPV1
Overall	79.3 ± 7.0	85.7 ± 9.6	81.1 ± 4.7	84.7	80.5
Experience
GE	76.4 ± 6.6	82.1 ± 9.2	78.0 ± 3.7	81.0	77.7
Trainees	81.0 ± 7.1	87.8 ± 9.9	82.9 ± 4.5	86.9	82.2
P value	0.320	0.378	0.098
Location
Proximal	74.6 ± 30.9	80.0 ± 29.7	75.6 ± 30.1	78.9	75.9
Distal	84.2 ± 29.0	88.9 ± 8.8	86.0 ± 23.4	88.4	84.9
P value	0.353	0.547	0.187
Size
Diminutive	63.2 ± 33.3	90.2 ± 7.8	74.2 ± 29.1	86.6	71.0
Non-diminutive	97.2 ± 7.2	27.32	93.1 ± 18.3	57.2	90.7
P value	< 0.001		0.008
Morphology
Polypoid	81.8 ± 25.1	85.1 ± 20.0	83.1 ± 23.0	84.6	82.4
Non-polypoid	75.4 ± 35.0	87.9 ± 13.9	77.3 ± 32.8	86.2	78.1
P value	0.536	0.829	0.470
Image quality
Excellent	89.3 ± 23.1	93.5 ± 6.9	90.3 ± 20.3	93.2	89.7
Good	63.6 ± 33.3	77.9 ± 23.4	68.4 ± 30.5	74.2	68.2
P value	0.010	0.117	0.007

Data are expressed as mean ± SD.

¹Based on our sensitivity and specificity data and literature data regarding prevalences of non-adenomatous and adenomatous polyps;

²Based on 1 case only, no statistics performed. GE: Gastroenterologist; PPV: Positive predictive value; NPV: Negative predictive value.

Table 5 Kappa values reflecting agreement of the endoscopist prediction with formal histopathology

	Kappa range	Interpretation1
All images (n = 50)
All predictions	0.453-0.737	Moderate–substantial agreement
High confidence predictions	0.519-0.821	Moderate-substantial agreement
Excellent quality images (n = 29)
All predictions	0.621-0.828	Substantial-almost perfect agreement
High confidence predictions	0.709-0.900	Substantial-almost perfect agreement

¹Interpretation according to Landis and Koch (reference 37).